Along with development of the technology and progression of the society, people increasingly depends day by day the aspect of information communication and transmission. And display components, which are treated as the primary carriers and physical infrastructures of the information exchange and transmission, currently become hot spots and highlands where numerous scientists engaged in information optoelectronic researches compete to seize.
The quantum dot display technology has comprehensively upgraded various dimensions of color gamut coverage, accuracy, red, green, and blue color purity, etc., which is regarded as the dominant position of the global display technology, and which it is also seen as the global display technology revolution, wherein the full color gamut display can be revolutionary accomplished, and the image colors get the most really restituted.
Quantum Dots (as so-called “QDs”), which also called semiconductor nanocrystals, are composed of binary or ternary inorganic nanoparticles from group II-VI or group III-V elements. Currently, the great researches are made primarily for binary compounds CdE of cadmium (Cd) (‘E’ denotes sulphur (S), selenium (Se), or tellurium (Te)). A common particle size of the quantum dot is in 2-10 nm, and different size quantum dots have different bandwidths. While a size of a quantum dot is lesser than Bohr radius of its exciton, electrons and holes of the quantum dot are confined by the quantum, the original contiguous band is transitioned into a discrete energy level structure, which can emit fluorescent light after excited.
Compared with the conventional fluorescent material, the quantum dots have a number of unique properties that: (1) an emission peak of the fluorescent light is narrow (where a common full width at half maximum thereof is in 20˜30 nm) and expressed in symmetrical distribution; (2) a luminous color of the fluorescent light is adjustable; (3) an optical stability thereof is better; and (4) a lifetime of the fluorescence is longer, and its biocompatibility is great.
Nevertheless, if quantum dots are applied within a liquid crystal cell (cell) of a liquid crystal display device (TFT-LCD), it is required to make quantum dot to achieve a polarizing property, such that quantum rod (Quantum Rod, as so-called ‘QR’) is created. Quantum rod denotes an one-dimension material which would be affected by the quantum confinement effect in two-dimension directions, most of the nanomaterials are composed of group II-VI or group III-V elements. Due to the quantum confinement effect, transportations of electrons and holes therein are suffered with limitations to facilitate the contiguous band structure transitioning into a discrete energy level structure. When the sizes of the quantum rods are different from each other, quantum confined levels of the electrons and holes are inconsistent with each other, and the discrete energy level structures are different. After suffered with excitation of external energy, different-size quantum rods promptly emit light with different wavelengths, namely, a variety of colored lights.
The quantum rod can emit linearly polarized light, and namely, the light from the quantum rod along a length direction of the quantum rod have linear polarization. However, since expressed in a random-mode arrangement under the ordinary manner, the quantum rods can not exert its linear polarization property. Thus, for displaying industry, it is a significant focus on the research of how to make the quantum rods in the liquid crystal cell to reach a stabilized orientation arrangement.